Nitrogen dioxide vapor penetration of chlorobutyl rubber SCAPE under operational conditions

Operational self contained atmospheric protective ensembles (SCAPE suits) and fabric from the suits were subjected to a series of tests designed to determine the amount of exposure a wearer of the suit would receive if a spill of the hypergolic oxidizer nitrogen tetroxide (N2O4) should occur nearby. The results of these tests show that a wearer of a "stock" SCAPE suit equipped with a standard liquid air pack, if exposed to a spill resulting in a 26 percent increase of oxidizer in the surrounding atmosphere, will experiment no detectable concentration of nitrogen dioxide (NO2) inside the suit for 15 minutes. Thereafter, the NO2 concentration within the suit will increase for 35 minutes at a rate of 0.07 ppm per minute and then at a gradually decreasing rate until an equilibrium concentration of 3.4 ppm is attained after 100 minutes. Momentary increases of as much as 1.6 ppm can be expected if the wearer were to rise quickly from a squatting position, but the additional NO2 would be dissipated within three minutes. The effect of liquid and vapor N2O4 and of liquid monomethylhydrazine on permeation rates and tensile strength of the SCAPE suit fabric was also investigated

Analysis of surface tris (2,3-dibromopropyl) phosphate on chlorobutyl rubber SCAPE suits

Tris (2,30-dibromopropyl) phosphate was used to confer flame retardant properties on butyl rubber formulations used in protective clothing such as the self-contained atmospheric protective ensembles (SCAPE suits) worn at Kennedy Space Center in support of Apollo, Skylab, and Apollo-Soyuz missions since 1966. Because tris (2,3-dibromopropyl) phosphate is mutagenic, surface concentrations of the compound in SCAPE suits were investigated as were as potential methods of removing or isolating it. Analytical procedures for determining surface concentrations of the tris compound on non-porous materials are described. Soap-and-water washing is the most efficient method of removing the compound from fabricated SCAPE suits and unused material

Triboelectrostatic Separation of Mineral Matter from Slovakian Coals

V èlánku sú diskutované niektoré technické aspekty triboelektrostatickej separácie a výs-ledky aplikácie tohto postupu pri úprave troch typov uhlia, konkrétne energetického uhlia z Cíg¾a, Handlovej a Novák. Bolo zistené, e úèinnos separácie ve¾mi úzko závisí na druhu separovan uhlia. Prvé výsledky preukázali súvislos medzi úèinnosou separácie obsahom popola v uhlí

Tube-wall methanation reactors with combined diffusion and kinetic resistance /

Includes bibliographical references (p. 14).Mode of access: Internet

Elaboration and mechanical characterization of multi-phase alumina-based ultra-fine composites

Al2O3-10 vol.% YAG and Al2O3-10 vol.% ZrO2 bi-phase composites as well as Al2O3-5 vol.% YAG-5 vol.% ZrO2 tri-phase composite were developed by controlled sur- face modi\ufb01cation of an alumina powder with inorganic pre- cursors of the second phases. Green bodies were produced by dry pressing and slip casting and then sintered at 1500 \ub0C. In particular, slip casting led to fully dense, defect-free, and highly homogenous samples, made of a \ufb01ne dispersion of the second phases into the micronic alumina matrix, as observed by SEM. The mechanical characterization proved the pre- dominant role of the \ufb01nal density on the Vickers hardness, while the elastic modulus was affected by the volume fraction of the constituent phases, in fairly good agreement with the rule of mixture prediction. The fracture toughness values of the bi- and tri-phase materials were similar, and their crack paths revealed the importance of the thermal residual stresses at the matrix-reinforcement interfaces, promoting inter- granular propagation